Classifications

• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03C—PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES; PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY
  • G03C1/00—Photosensitive materials
  • G03C1/76—Photosensitive materials characterised by the base or auxiliary layers
  • G03C1/815—Photosensitive materials characterised by the base or auxiliary layers characterised by means for filtering or absorbing ultraviolet light, e.g. optical bleaching
  • G03C1/8155—Organic compounds therefor
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S430/00—Radiation imagery chemistry: process, composition, or product thereof
  • Y10S430/132—Anti-ultraviolet fading

Definitions

• the present invention relates to UV sensitive negative acting silver halide photographic elements, and more particularly to UV sensitive negative acting silver halide photographic elements which have extended UV exposure latitude.
• Negative acting silver halide elements which are intended for exposure to UV emitting lamps (such as metal halide lamps) may be afforded some degree of white light handeability by the use of filter dyes either in the emulsion layer or in a non light-sensitive layer. Typically, the dye will particularly absorb visible light and prevent exposure of the radiation sensitive layer by this light.
• the filter dye is chosen not to greatly interfere with intentional exposure to UV radiations. Examples of silver halide elements incorporating said filter dyes are disclosed in US Pat. Nos. 4,140,531, 4,232,116 and 4,495,274 and EP Pat. Application No. 146,302 where blue absorbing dyes are used which are bleachable during processing.
• the first patent refers to polymeric versions of the above dye class and is fairly far removed from our proposed use.
• the second patent refers to particular versions of formula above in which R 1 and R 2 are allyl groups.
• the third patent refers to particular versions of the formula above in which R 1 is a short C 1 -C 3 alkyl chain and R 2 is a long alkyl chain> C1 o.
• Advantages are claimed for improved absorption profiles and reduced speed loss compared to the derivatives claimed in Reissue Patent 30,303. Again their main application is for UV filter dyes in the color negative constructions. Said dyes are hydrophobic and presumably would not be bleached in processing.
• a UV sensitive negative acting silver halide photographic element for contact processes which have increased UV exposure latitude.
• Said element comprises a support, a hydrophilic colloidal silver halide emulsion layer comprising UV sensitive negative acting silver halide grains, and one or more hydrophilic colloidal layers, wherein said silver halide emulsion is reactively associated with a water removable UV absorbing compound having at least 80% of absorption in the range of 350 to 400 micronmeters.
• the two requirements in the present invention are 1) that the UV dye must be present in the negative acting silver halide emulsion layer or in a layer coated onto the support on the same side of the emulsion layer for increasing the exposure latitude, and 2) the UV dye be removed during the chemical processing for optimal subsequent contact exposures.
• the present invention relates to a UV sensitive negative acting silver halide photographic element comprising a support, a hydrophilic colloidal silver halide emulsion layer comprising UV sensitive negative acting silver halide grains, and one or more hydrophilic colloidal layers, wherein said silver halide emulsion is reactively associated with a water removable UV absorbing compound having at least 80% of absorption in the range of 350 to 400 micronmeters.
• the UV absorbing compounds for use in the negative acting silver halide photographic element according to the present invention correspond to the general formula: in which:
• G represents an electron withdrawing group of any electron withdrawing groups known in the art such as, for example, CN, N0 2 , COOR or SO 2 R wherein R represents an alkyl group, preferably an alkyl group having 1 to 10 carbon atoms, more preferably an alkyl group having 1 to 4 carbon atoms, or an aryl group (such as phenyl or naphthyl), preferably an aryl group having 6 to 20 carbon atoms, more preferably an aryl group having 6 to 10 carbon atoms, and at least one of Ri, R 2 and G is substituted with a water solubilizing group of any water solubilizing groups known in the art such as, for example, a COOH group or an alkaline metal or aonium salt thereof, a S0 3 H group or an alkaline metal or aonium salt thereof, a hydroxy group, a quaternary aonium salt containing group, a phosphate group or a polyoxyalkylene group.
• R
• UV absorbing compounds for use in the negative acting silver halide photographic elements according to the present invention correspond to the general formula: in which:
• R 3 represents an alkylene group having 1 to 10 carbon atoms whose carbon atom chain may comprise divalent groups such as, for example, -O-, -S-, -COO- or S0 2 -.
• the UV absorbing compounds of the photographic elements according to the present invention have a strong absorption in the region of the electromagnetic spectrum at the boundary between the UV and the visible region.
• the UV absorbing compounds according to this invention have a peak or plateau in their absorbing spectra around 380 micronmeters. At least 80% of their absorption is in the range of from 350 to 400 micronmeters, their absorption below 350 micronmeters being such as not to affect significantly the response of the silver halide emulsion to the UV radiations of the exposure light, preferably such as not to absorb more than 30% of the radiation emitted by exposure lamps.
• the UV absorbing compounds of the photographic elements according to the present invention are highly soluble in water, so that they can be washed out of the element during processing, without a significant retention of UV absorption.
• the absorption of the element in Dmin areas after processing is, in the range from 300 to 400 micronmeters, less than 0.10.
• the UV absorbing compounds of this invention can be prepared according to methods well known in the art.
• the UV absorbing compounds of general formulas (I) and (II) can be prepared by treating an appropriate amine compound containing the water solubilizing group with an appropriate intermediate in an organic solvent at boiling temperature followed by usual techniques for isolating the compounds.
• Useful intermediates are for example described in US Patent 4,045,229.
• the product is soluble in water upon addition of a stoichiometric quantity of NaOH.
• the UV absorbing compounds are used in an hydrophilic colloidal silver halide emulsion layer and/or an adjacent hydrophilic colloidal layer.
• said adjacent layer is nearer to exposure light source than the silver halide emulsion layer.
• the UV absorbing compounds may be added in the form of a water solution to the hydrophilic colloidal coating composition of a silver halide emulsion layer and/or an adjacent layer.
• the adding quantity of the UV absorbing compounds is generally from 0.0001 to 0.1 moles per mole of silver halide, and preferably from 0.001 to 0.01 moles per mole of silver halide.
• the addition may be made in any step of the process for preparing the UV sensitive negative acting silver halide emulsion, preferably after having completed the second ripening and before coating.
• silver halide emulsions for use in the UV sensitive negative acting photographic elements according to this invention may be preferably selected from high chloride silver halide emulsions. They preferably contain at least 50% mole and more preferably at least 75% mole of silver chloride, the higher the silver chloride content, the lower the natural blue and visible light sensitivity, even if the UV radiation sensitivity remains high.
• the silver halide emulsions to be used in UV sensitive negative acting type photographic elements according to the present invention are emulsions wherein at least 75% by weight of all silver halide grains are silver halide grains wherein at least at 80% mole is silver chloride.
• the remaining silver halide, if any, will be silver bromide and/or silver iodide but the latter should normally be present in an amount not exceeding 1% mole.
• the dyes include, for example, oxonol dyes, benzylidene dyes, and the like, which can be bleachable or washable during processing. Examples of useful dyes are described, for example, in US patent 4,140,531. In conventional emulsions sensitizing dyes are used to extend the sensitivity of the emulsion to longer wavelengths of visible light. This is not required with the emulsions used in the present invention. It also appears to be desirable for the high chloride silver halide emulsions to have a relatively small grain size, e.g. a mean grain size of from 0.05 to 0.6 micron, the preferred grain size being in the range of from 0.05 to 0.3 microns and the most preferred being from 0.05 to 0.1 micron.
• the high chloride silver halide grains preferably have a cubic shape, but may have other shapes, such as octahedra, spheres, tabular shapes, etc.
• silver halides may be prepared in the presence of at least a doping metallic element of the 8th Group of the Periodic Table of Elements, such as rhodium, iridium and ruthenium, which acts as electron acceptor.
• Said doping element is preferably chosen among water-soluble iridium salts or water-soluble rhodium salts.
• Iridium salts include iridium and alkaline metal halides, such as potassium iridium (III) hexachloride and sodium iridium (III) hexabromide.
• Rhodium salts include rhodium halides, such as rhodium (III) trichloride and rhodium (IV) tetrachloride and rhodium and alkaline metal halides such as potassium rhodium (III) hexabromide and sodium rhodium (III) hexachloride. These salts may be added in a quantity of from 0.5x10- 4 to 10x10- 4 moles, and preferably from 2x10- 4 to 7x10- 4 moles per mole of silver halide.
• Gold compounds used for chemical sensitization, include alkali metal chloroaurates, chloroauric acid, gold sulfide, gold selenide, and the like. Said gold compounds are generally used in a quantity of from 1x10- 6 to 1x10- 4 moles per mole of silver halide.
• the UV sensitive negative acting silver halide emulsions of the photographic elements according to this invention may contain various other photographic additives which include desensitizers, solarization accelerators, stabilizers, hardeners, coating aids, preservatives, matting agents, antistatic agents, and the like, as described, for example, in US Patent 4,495,274.
• Gelatin is generally used as hydrophilic colloid for the silver halide photographic elements of the present invention.
• hydrophilic colloids gelatin derivatives, natural substances such as albumin, casein, agar-agar, alginic acid and the like, and hydrophilic polymers such as polyvinyl alcohol, polyvinylpyrolidone, cellulose ethers, partially hydrolized polyvinyl acetate, and the like can be used in addition to or instead of gelatin.
• gelatin can be partially substituted with polymer latexes obtained by emulsion polymerization of vinyl monomers, such as polyethylacrylate latexes, to improve the physical characteristics of the photographic layers.
• Support bases used in the direct-positive silver halide photographic elements according to this invention can be any of the conventionally used support bases, such as glass, cloth, metal, film including for example cellulose acetate, cellulose acetate-butyrate, cellulose nitrate, polyester, polyamine, polystyrene, and the like, paper including baryta-coated paper, resin-coated paper, and the like.
• the negative acting silver halide photographic elements according to this invention may be used in the field of Graphic Arts for various purposes, such as, for example, for contacting, for reproduction, for making offset printing masters, as well as in radiography for special purposes, in electron photography, and the like, where high UV sensitivity is required together with low blue light sensitivity.
• the negative acting silver halide photographic elements according to this invention are higly UV sensitive and give high contrast and low minimum density (fog) when they are exposed with light rich in UV rays, and have extended UV exposure latitude.
• a silver halide emulsion containing 98% mole chloride and 2% mole bromide was prepared by adding simultaneously and under stirring, over a period of 25 minutes, with the double-jet technique, water solution B and water solution C to water gelatin solution A, said water solutions having the composition reported hereinbelow.
• the gelatin solution was kept at constant temperature of 35 ° C.
• the addition rate of solution C was constant, while the addition rate of solution B varied such as to maintain the millivolt of the emulsion thus formed at a value of 380 ⁇ 10 mv measured with a specific electrode for Br ion and a reference electrode of the saturated Ag/AgCI type.
• Further additions were made to the individual portions as indicated in Table 1, followed by coating, at a silver coating weight of 2.3 g/m 2 , onto a polyethylene terephthalate support base which was backed with a green antihalation layer.
• the films were exposed through a 0.15 continous wedge.
• the exposing lamp was a Philips HPA 2000 UV lamp and the films were exposed for 10 at 1 meter distance.
• the room light was that of an Osram 40W type 21 LumiluxTM white
• the exposed films were developed in 3M RDC Developer for 20 at 40 ° C and fixed in 3M Fixroll Fixer.
• the following Table 1 reports the speed at density of 1 (D1 toe contrast (D2), medium contrast (D3), D-min (D4) and D-max (D5).
• the optimum contact exposure is that giving a Dmax >4.0 with a sufficient dot reproduction in the midtones.
• the test consisted of making a first contact exposure at 8x units overexposure (used to eliminate dirt, spots or paste-up lines) and then a second contact exposure at the same contact overexposure measuring the resulting dot enlargment.
• Table 2 reports the 50% dot reproduction (% dot gain) of the above films at the optimum contact exposure and at the first (negative) and second (positive) contact overexposures and shows how dramatically the addition of the UV absorbing compound added to the negative acting emulsion affects the resulting dot reproduction in overexposure contacting.
• the Dye A above is an oxonol dye corresponding to the formula:

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• 1991
  • 1991-07-30 IT ITMI912108A patent/IT1250717B/it active IP Right Grant
• 1992
  • 1992-07-07 EP EP92111476A patent/EP0525445A1/de not_active Ceased
  • 1992-07-13 US US07/912,777 patent/US5316901A/en not_active Expired - Fee Related
  • 1992-07-30 JP JP4203563A patent/JPH05249596A/ja active Pending

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